Is it because of the different columns that Copper and Iron are in, in the periodic table? What do the columns represent?
columns represent how much atoms they can give/take. and since iron and copper are a metal, and they can have different ions, then you'll have to know what the atom bonded to to figure out what (#) it is. (at least that's what my chem teacher says, she says it's an ezier way to figure out how much electrons atoms can give/take just by looking at the periodic table)
the (I) (II) means what version of the element it is. some elements can be found commonly with different charges but are both stable enough to exist for a period of time, you get iron (II) and (III) because theyre both stable but if you get iron (I), it wont be stable.
Sort of, but it's more than that. The columns represent groups of elements that have similar chemical properties. The transition metals are a bit tricky when it comes to charges of the ions. Part of the answer lies in the electron configurations of the two metals: Fe: [Ar] 3d8 4s2 Cu: [Ar] 3d10 4s1 The 4s electrons come off first, and generally leave none behind. In the case of Cu, this gives a +1 ion. In the case of Fe, this gives a +2 ion. From here, both can lose another electron fairly easily, giving Cu+2 and Fe+3. If you don't understand electron configurations, just realize that Cu has one electron in the fourth shell, while Fe has two. Those outermost electrons are relatively easy to pull off the atom. The inner electrons (the 3d electrons) are a little harder to pull off, but one more can be removed in each case. As you remove more electrons, it gets more difficult to remove more since there's a stronger attraction between the positively charged nucleus and the negatively charged electrons. There's more to it than that, but that should suffice for now.
copper and iron are just two examples of elements with variant charges. Those charges have been established through experimentation and have to do with the properties of the elements (specifically, how they gain and lose electrons in reactions). It doesn't have to do with columns like it does for other elements with invariant charges. For example, potassium (K) has an invariant charge. It will always be +1 in a reaction. It is in the 1st column (group). All the other group 1 elements share this trait. Copper I has a charge of +1, and copper II has a charge of +2, but copper is not found in group 1 or group 2 of the periodic table
